The present invention relates to a zoom lens system that is suited to mounting in a digital camera or an information terminal such as a mobile phone that is equipped with a digital camera function.
A digital camera that uses an image pickup device such as a CCD or a CMOS to obtain an image formed by a lens as digital data is known. An information terminal such as a mobile telephone, a cellular phone etc., in which a digital camera is incorporated is also known.
Japanese Laid-Open Patent Publication No. 2001-296476 discloses a zoom lens composed of three lens groups with negative, positive and positive refractive powers in that order from the object side, where the first group consists of two lenses, the second group consists of four lenses, and the third group consists of one lens, making a total of seven lenses. To make such zoom lens systems even more compact, there is demand for a further reduction in the number of lenses that construct the lens system.